Mal, Evie, Carlos and Jay try to adjust to life in Auradon, but Mal becomes overwhelmed with pressure and returns to her roots.
When the pressure to be royally perfect becomes too much for Mal, she returns to her rotten roots on the Isle of the Lost where her archenemy Uma, the daughter of Ursula from The Little Mermaid, has taken her spot as self-proclaimed queen of the run-down town. Uma, still resentful over not being selected by Ben to go to Auradon Prep with the other Villain Kids, stirs her pirate gang including Captain Hook's son Harry and Gaston's son Gil, to break the barrier between the Isle of the Lost and Auradon, and unleash all the villains imprisoned on the Isle once and for all.—Disney Channel
Mal is under too much pressure of being royal with Prince Ben and returns to the Isle of the Lost where she comes across her enemy Uma (daughter of Ursula). Uma is angry at Prince Ben for not inviting her to Auradon Prep and creates a pirate gang including Harry (son of Captain Hook) and Gil (son of Gaston) to break down the magic barrier and unleash evil into Auradon. Can Evie, Carlos, Jay and Ben stop Mal turning to her wicked ways?
Under lots of pressure from royalty, Mal returns to the isle of the lost to find her enemy Uma, the daughter of Ursula, has taken over. Uma has a team of pirates including Harry, the son of Captain Hook, and Gil, the son of Gaston, to break the barrier between the Isle of the Lost and Auradon so villain kids can live there. Now it is up to Evie, Jay, Carlos, and Ben to stop Mal from becoming evil again and to stop Uma, Gil, and Harry from breaking the barrier.
Mal struggles with her new celebrity life as the girlfriend of King Ben, putting a spell on her hair making it blonde, and maintaining a princess-like personality that she is uncomfortable with. She admits her issues to her friends Evie, Carlos, and Jay, but they are content with their new lives in Auradon and do not wish to return to the Isle of the Lost. Evie scolds Mal for relying on her mother's spell book to solve her issues. Carlos, wishing to ask Jane to the upcoming Cotillion dance, turns to Mal for help to be honest with her. Mal gives him a sweet that will make him speak the truth, but his dog Dude eats it, magically speaking the truth in English and very frankly as a result..
The selected kids of villains continue their studies at Auradon Prep school. Mal dreams of reigning chaos by distributing altered apples that makes everybody in the Auradon Kingdom to become a rebel and have "fun" in wicked ways.
However, in reality, Mal (Dove Cameron) (daughter of Maleficent) struggles with her new celebrity life as the girlfriend of King Ben (Mitchell Hope) (son of Belle (Keegan Connor Tracy) and Beast (Dan Payne)), putting a spell on her hair making it blonde, and uncomfortably maintaining a princess-like personality. Ben and the Fairy Godmother work hard to keep Mal away from the media spotlight, who is keen to know whether Maleficent is still a lizard.She confides her issues in her friends Evie (Sofia Carson) (daughter of The Evil Queen), Carlos (Cameron Boyce) (son of Cruella De Vil) and Jay (Booboo Stewart) (son of Jafar), but they are content with their new lives in Auradon and do not wish to return to the Isle of the Lost.Mal says that she has to attend dozens of official functions posing as a pretty princess and she is sick of it. Mal wants to run wild and break all the rules.
Evie scolds Mal for relying on her mother's spell book to solve her issues. Evie wants Mal to put her spell book in the museum, which is where Evie put her mother's magic mirror. Evie is still friends with Doug (Zachary Gibson) (son of Dopey), and Chad (Jedidiah Goodacre) (son of Cinderella and Prince Charming).Chad still pines for Audrey since they broke up.Lonnie beats Jay at sword practice, but Chad refuses to select her for the team. Chad says that the rules explicitly state that the team can comprise of a captain and 8 men. Jay is the captain, and he is forced to agree with Chad.
Carlos, wishes to ask Jane (Brenna D'Amico) (daughter of the Fairy Godmother (Melanie Paxson)) to the upcoming Cotillion dance, but every time he tries Jane goes off on a complete tangent and misunderstands his intentions. Jane gets the idea that Carlos wants to skip the Cotillion dance and she agrees with him. Jane is on the organizing committee for the dance event and has a million things seeking her attention.Carlos turns to Mal for help with honesty. Mal gives him a sweet that will make him speak the truth, but his dog, Dude (Bobby Moynihan), eats it, magically speaking the blunt truth in English.
Mal is shocked to learn that the Royal Cotillion is basically an engagement party for Ben and Mal which will eventually lead to a wedding. Mal is not OK with her entire life planned out by other people, without her having any say in it. Mal begins to panic and in one instance her eyes turn a deep shade of green.
Ben eventually discovers Mal's reliance on magic (her blonde hair, speed reading spells for books and cooking spells for their picnics), and she comes clean about her insecurities (Mal says that she is not a pretty pink princess and not a lady of the court. This is all new to her and she feels that she is a fake), causing a falling-out. Mal decides that she does not belong in Auradon. She takes her mother (who is now a lizard in a showcase in Mal's room) and leaves.
Mal returns to the Isle (she uses the book of spells to cross the ocean around the Island), now ruled by her former friend Uma (China Anne McClain), Ursula's daughter, along with Harry (Thomas Doherty) and Gil (Dylan Playfair), the sons of Captain Hook and Gaston. When Mal was at the Isle of the Lost, she was the ruler and she deemed Uma not fit to be in her group. Uma is not content with getting Mal's leftovers and wants to control Auradon. She wants what Mal is about to get, true power.Mal visits hairstylist Dizzy Tremaine (Anna Cathcart), Drizella's daughter, who restores her signature purple hair, saying she felt that Mal's blonde hair was unnatural. Harry discovers Mal's return and informs Uma.
Ben, Evie, Jay and Carlos learn of Mal's departure. Ben is depressed and says that he pushed Mal when he should have been understanding and wants to apologize. Evie, Jay and Carlos accompany Ben as he doesn't know how the Isle works and would be lost without them. Evie makes Ben promise that she won't be stuck at the Isle and wants to come back to Auradon.Evie gives Ben a complete makeover and teaches him to drop his manners so he can survive on the Isle.
They sneak onto the Isle to find her, but Gil recognizes them. The group takes Ben to Mal's house.Ben confronts Mal, who rejects his feelings for what she thought was both his sake and Auradon's. Mal says that she is home, and that she cannot fit in Auradon. She does not want Ben to mess up his perfect life on her account.
Ben leaves dejected, only to be captured by Uma. Uma wants Mal to come to her for a meeting, and Mal blames her friends for bringing Ben to the Isle.Mal and Uma arm wrestle for Ben and Fairy Godmother's wand, which Uma wins. Uma then orders Mal and her friends to retrieve the Fairy Godmother's wand or Ben dies.Carlos and Jay return to Auradon Prep, where they create a replica of the wand using a 3D printer. They are caught by Lonnie (Dianne Doan), Mulan's daughter, who blackmails them into letting her come, having previously been rejected from Jay's sports team based on her gender.
Back on the Isle Evie and Mal work together to make smoke bombs using Dizzy's chemical's kit. Evie realizes that Dizzy is immensely talented and wants to be in Auradon. Dizzy is still very happy for Evie and says that at least one of them gets to live their dream.Mal is clear that she will never return to Auradon but tells Evie that she should return as she is an Auradon girl to the core and belongs in that world of high fashion.
Uma speaks with Ben, bitter that she and the others were not chosen to go to Auradon. Ben takes this into account and invites her to Auradon, but Uma instead plots to make her own way there. Ben says that his plan was to start with 4 transfers and then plan for more, once society became more accepting of the people from the Isle. Ben wants Uma to come to Auradon and be part of the solution.
Mal's group return, handing over the fake wand in exchange for Ben. Uma wants a demonstration of the wand and Mal pretends to put a spell on Dude, and makes it seem like he can suddenly speak like a human.
But soon, Uma realizes the forgery when she tries to use the wand to tear down the magic barrier around the Isle. The group flee back to Auradon (by detonating the smoke bombs to cover their tracks and the group fighting off the attackers with swords), but Mal and Ben's relationship is still rocky. They ride a car back to Auradon.The villains' children come to terms that they cannot run from their pasts and agree to be honest with themselves and each other. Carlos confesses to Jane but struggles a little bit, while Jay appoints Lonnie as the captain of his team.
Aboard a ship during the Cotillion, Ben stuns everyone by appearing with Uma, whom he declares as his true love and announces he will destroy the barrier on the Isle. Jane unveils a stained-glass display Ben commissioned to show his affection for Mal, who realizes he loved her for who she was all along. Suspecting Uma has given him a love potion, Mal confesses her love for Ben and kisses him, breaking the spell.
Enraged, Uma leaps into the water using Ursula's magic seashell to transform into an octopus, and Mal fights back as a dragon. Ben intervenes, quelling the battle, and Uma returns the ring that Ben had originally given her when he had declared her as his true love. She leaves, despite his offer still standing.
Mal and Ben reunite, Mal surrendering her spell book to the Fairy Godmother (Melanie Paxson). Evie requests that Dizzy be allowed to attend Auradon Prep; when Dizzy is offered, she excitedly accepts.In a mid-credits scene, Uma addresses the audience, promising that the story is not over.